Calcium magnesium and phosphate Calcium

Plasma calcium levels have been traditionally corrected to plasma albumin levels; this is now considered irrelevant, particularly at the low albumin levels seen in critically ill patients. Measurement of the ionised fraction is now considered more pertinent since it is the ionised fraction that is responsible for the extracellular actions of calcium, with changes in the ionised fraction being responsible for the symptomatology.

High calcium levels occur with hyperparathyroidism, certain malignancies and sarcoidosis while low levels are seen in renal failure, severe pancreatitis and hypoparathyroidism.